JP4195579B2 - Friction stir welding material and manufacturing method thereof - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a friction stir welding type material and a manufacturing method thereof, particularly, railway vehicles, ships, and manufacturing method of friction stir welding type material about to be used in large structures such as aircraft.
[0002]
[Prior art]
In general, two-sided structures (panels) such as long hollow materials that extend in the longitudinal direction are used for large structures such as railway vehicles, ships, and airplanes. When extruding die materials are joined together, for example, a butt joint portion is formed using MIG welding or the like. However, problems such as thermal distortion occur in the melt bonding method.
[0003]
On the other hand, Japanese Patent Publication No. 7-505090 discloses the joining of members by friction stir welding, and as a solid phase joining method, a rotary tool made of a material substantially harder than a workpiece is used. There is a joining method in which a workpiece is joined by plastic flow caused by frictional heat generated between the rotating tool and the workpiece by being inserted into the joining portion and moving while rotating the rotating tool.
[0004]
This friction stir welding method is substantially free of thermal distortion in the joining direction because the joining member can be joined in a solid phase state while the rotating tool is rotated and moved to be softened and integrated. In addition, there is an advantage that even an infinitely long member can be continuously solid-phase bonded in the longitudinal direction. Further, since the solid-phase bonding using the plastic flow of the metal by the frictional heat between the rotating tool and the bonding member, the bonding can be performed without melting. Further, since the bonding temperature is low, deformation after bonding is small. Since the joint is not melted, there are many advantages such as fewer defects.
[0005]
In such friction stir welding, since the joining is performed while pressing with a tool, a very large pressing force acts on the joint. Therefore, in order to prevent deformation of the mold material due to the pressing force, a support member that supports the pressing force on the side opposite to the tool is required.
[0006]
On the other hand, when performing friction stir welding, a tool having two shoulder portions so as to sandwich a pin (probe) at a predetermined interval from both ends is used as a tool. The mold materials are joined so as to be sandwiched from the direction. According to this method, since the joint portion is sandwiched between the front and back surfaces by the two shoulder portions, the pressing force is extremely small, and the above-described support member and the like are not necessary.
[0007]
However, when a tool having two shoulder parts (called a bobbin tool) is used, if there is a gap between the shoulder parts and the joint part, no pressure is applied to the joint part, resulting in a hollow defect. Resulting in. When the distance between the shoulder portions and the thickness of the joint portion are the same, the joint portion becomes thinner than the thickness other than the joint portion. For this reason, a problem may arise in the quality of a joined part.
[0008]
In addition, when a gap (gap) exists in the joint portion, when the joint portion is joined using the bobbin tool, the gap cannot be replenished, and a joint defect may occur.
[0009]
In order to deal with such a problem, for example, what is described in JP-A-2002-18580 is known (hereinafter referred to as a conventional example). In the conventional example, joining is performed by setting the joining thickness of the joining material sandwiched between the upper and lower shoulder portions to be larger than the interval between the upper shoulder portion and the lower shoulder portion. Specifically, in the conventional example, the joining portion of two joining materials facing each other is fitted, the joining thickness is locally thicker than the thickness other than the joining portion, and the joining portion thickness is further increased. It is larger than the interval between the upper and lower shoulder portions. This prevents the gap of the joint from changing due to frictional heat and prevents the thickness of the joint after joining from becoming thinner than the other parts.
[0010]
[Problems to be solved by the invention]
However, in the conventional example, it is necessary to make the thickness of the joint portion locally larger than the interval between the upper and lower shoulder portions in advance, and it is considered that the gap generated in the joint portion differs in the joining process (manufacturing process) Then, it is difficult to know in advance how much the thickness of the joint portion should be thicker than the portion other than the joint portion. In other words, considering the gap, it is extremely difficult to make the thickness of the joint portion locally larger than the interval between the upper and lower shoulder portions in advance, and if the gap is large, the thickness of the joint portion is reduced to the upper and lower shoulder portions. Even if it is locally larger than the interval, the gap may not be sufficiently filled in the joining process. For this reason, there exists a possibility that a joint defect may arise.
[0011]
The objective of this invention is providing the manufacturing method of the friction stir welding material which a joining defect does not produce.
[0012]
[Means for Solving the Problems]
According to the present invention, a circular shoulder for imparting frictional heat to a workpiece is rotated while imparting frictional heat to the front side or both sides of the butt joint between the mold members extending in the longitudinal direction, and the vicinity of the joint is plasticized. In a manufacturing method for forming a friction stir welding material by performing friction stir welding between workpieces while flowing,
The butt joint between the mold members is a fitting structure that is fitted in a width direction or a height direction, and a frictional force application surface side of the joint with the circular shoulder has a width region smaller than the diameter of the shoulder surface. The plate material is fixed along the extending direction of the joint portion, the tool entry end of the plate material is gradually thinned, and the frictional heat of the shoulder surface is applied to the joint portion via the plate material, A manufacturing method of a friction stir welding material characterized in that the mold members are joined to each other by plastic flow of the joint portion.
[0013]
According to this invention, the mold materials are fitted to each other at the joint portion, and the plate material having a width area equal to or smaller than the diameter of the shoulder surface is fixed to the frictional force imparting surface side along the extending direction of the joint portion. The thickness of the plate material can be easily set according to the gap of the part, and as a result, the gap can be sufficiently supplemented in the joining process. Therefore, no junction defect occurs.
[0014]
In the present invention, the tool is preferably a bobbin tool having a pair of shoulder portions located on both front and back sides of the joint with the probe interposed therebetween, and the distance between the pair of shoulder portions is equal to or greater than the thickness of the joint and the thickness of the plate is added. It is set smaller than this. If it does in this way, sufficient friction heat can be given to a joined part via a board material from a shoulder part, and friction stir welding can be performed favorably.
[0015]
In the present invention, the plate material is preferably the same material as the mold material or a material having a lower melting point, and is fixed by an adhesive whose evaporation temperature is lower than the temperature due to the frictional heat or by spot welding. It is fixed to. In this way, if the plate material is the same material as the mold material or a material having a lower melting point, the plate material is friction stir welded together with the mold material, and the plate material and the mold material are fixed with an adhesive. For example, fixing can be performed easily, and the adhesive evaporates in the process of friction stir welding because the evaporation temperature of the adhesive is lower than the temperature due to frictional heat, so there is no problem. Furthermore, if the plate material and the mold material are fixed by spot welding, temporary fixing can be easily performed.
[0016]
In the present invention, the cross-sectional area of the plate material is preferably 1 to 3 times the total area of the fitting gap generated in the joint. By prescribing in this way, the friction stir welding can be satisfactorily performed. In addition, even when the thickness of the plate material is set to be 1 to 3 times the fitting gap generated in the joint, friction stir welding can be performed satisfactorily.
[0017]
In the present invention, the width of the plate material is preferably not less than the width of the fitting portion formed in the joint portion and not more than the shoulder diameter. Here, since the width of the plate material is not less than the width of the fitting portion formed in the joint portion and not more than the shoulder diameter, the plate material does not protrude from the shoulder portion (that is, the tool), and the friction stir welding is performed satisfactorily. Can do.
[0018]
According to the present invention, the tool entry end of the plate is gradually thinned. If it does in this way, in friction stir welding, tools, such as a bobbin tool, can be easily inserted in the starting point of a joined part.
[0019]
Furthermore, can have contact to the onset bright, for example, the tool is a bobbin tool having a pair of shoulder portions located on both sides of the joint across the probe, the distance between the pair of shoulder portions of the joint thickness As described above, the thickness may be set to be smaller than the thickness of the plate material. The plate material may be the same material as the mold material or a material having a lower melting point, and the fixing may be performed at a temperature higher than the temperature caused by the frictional heat. You may make it fix to the said junction part by the adhesive agent with low temperature, or spot welding.
[0020]
In addition, the width of the plate member is not less than the width of the fitting portion formed in the joint portion and not more than the shoulder diameter, so that the fitting portion can be fitted by a separating operation in the width direction. Then, gradually thinned tool rush end of the plate.
[0021]
DETAILED DESCRIPTION OF THE INVENTION
The present invention will be described below with reference to the drawings. It should be noted that the dimensions, materials, shapes, relative arrangements, etc. of the components described in the illustrated examples are not intended to limit the scope of the present invention, but are merely illustrative examples, unless otherwise specified. Absent.
[0022]
Referring to FIG. 1, the illustrated tool 11 includes a thin probe 12 and a pair of circular shoulder portions 13 and 14 sandwiching the probe 12, and such a tool is called a bobbin tool. Circular shoulder surfaces 13 a and 14 a are generated on the lower surface of the shoulder portion 13 and the upper surface of the shoulder portion 14, and the shoulder surfaces 13 a and 14 a serve as a butt joint portion between the mold materials that are workpieces, as will be described later. Frictional heat is applied.
[0023]
As shown in the figure, the diameter (A) of the shoulder portions 13 and 14 is larger than the diameter of the probe 12, and the interval between the shoulder portions 13 and 14 (that is, the interval between the shoulder surfaces 13a and 14a) (B) is a plate material to be described later. And the thickness of the butt joint.
[0024]
With reference to FIG. 2, here, for example, the joining of long mold materials used in a railway vehicle will be described. The long mold materials 21 and 22 are, for example, extruded mold materials having a U-shaped cross section, and are made of an aluminum alloy. In the illustrated example, the mold material (long mold material) 21 extends in the longitudinal direction (in FIG. 2, from the front side to the back side (long direction) in the drawing) (for example, about 25 meters), and the face plate portion 21a and 21b. The face plate portions 21a and 21b are held at a predetermined interval by a rib member 21c arranged perpendicular to the face plate portions 21a and 21b. A joint portion is defined at one end portion (right side in the drawing) of the long mold member 21, and a concave fitting groove 21 d is formed in the one end portion (that is, one end portion of the face plate portions 21 a and 21 b) in the width direction. Yes. And this fitting groove is extended in the elongate direction.
[0025]
Similarly, the long mold material 22 extends in the longitudinal direction and includes face plate portions 22a and 22b. The face plate portions 22a and 22b are held at a predetermined interval by a rib member 22c arranged perpendicular to the face plate portions 22a and 22b. A joining portion is defined at one end portion (left side in the figure) of the long mold member 22. The one end (that is, one end of the face plate portions 22a and 22b) is formed with a convex fitting protrusion 22d in the width direction, and the fitting protrusion extends in the longitudinal direction.
[0026]
When joining the long mold members 21 and 22 by friction stir welding, the long members 21 and 22 are fixed on a gantry (not shown), and the fitting protrusion 22d is fitted into the fitting groove 21d. The long members 21 and 22 are combined (matched). That is, the long mold members 21 and 22 are combined by the fitting structure. At this time, a fitting gap (fitting gap) is inevitably generated. When such a fitting gap is generated, a bonding failure may occur due to the fitting gap as described above. For this reason, the board | plate material 31 is previously fixed along the extension direction of a junction part along a junction part. The plate material 31 is the same material as the long mold materials 21 and 22 or a material having a melting point lower than that of the long mold materials 21 and 22, and the temperature due to frictional heat applied by the bobbin tool 11 when the plate material 31 is fixed. The plate 31 is fixed using an adhesive having a lower evaporation temperature.
[0027]
In FIG. 2, the plate material 31 is fixed to the front surface side of the joint portion, but the plate member 31 may be fixed along the joint portion on the back surface side of the joint portion. That is, the plate material 31 is fixed to the frictional force applying surface side to which the bobbin tool 11 applies the frictional force.
[0028]
Here, referring also to FIG. 3 and FIG. 4, where G is the fitting width and C is the width of the plate material 31, G <C ≦ A (A is the diameter of the shoulder portions 13 and 14). . Furthermore, if the thickness of the joint portion, that is, the thickness of the long mold materials 21 and 22 (in other words, the thickness of the face plate portions 21a, 21b, 22a, and 22b) is D, and the thickness of the plate material 31 is E, D ≦ B (B is an interval between the shoulder portions 13 and 14), and 2 × E + D> B is set.
[0029]
When performing friction stir welding, the bobbin tool 11 is moved from the start point S to the end point (not shown) of the joint portion extending in the longitudinal direction. In the illustrated example, the bobbin tool entry end of the plate material 31 is used. Is gradually thinned like a knife edge. That is, the plate material 31 is inclined in a knife edge shape so that the thickness thereof becomes thinner toward the front at the start point S to form an inclined surface (that is, the start point S is an inclined end).
[0030]
Now, the bobbin tool 11 is inserted from the starting point S by rotating the probe 12 and the pair of shoulder portions 13 and 14 integrally (for example, in the direction indicated by the thick arrow in FIG. 4). At this time, as described above, since the plate 31 is inclined in a knife edge shape so that the thickness thereof is thin, at the starting point S, the thickness of the joint is substantially equal to D. Since D ≦ B, the bobbin tool 11 can be easily inserted into the joint.
[0031]
The bobbin tool 11 is moved along the joint while rotating. As described above, since the plate material 31 is inclined in a knife edge shape so that the thickness thereof is reduced, the sum of the thickness of the plate material 31 and the thickness of the joint portion after the start point S is the shoulder portions 13 and 14. As a result, the shoulder portions 13 and 14 respectively apply a frictional force to the joint portion via the plate material 31. Then, after passing the intrusion end (that is, the front end portion of the plate material 31), the total thickness of the joint portion and the plate material 31 becomes 2 × E + D, and a strong frictional force is applied to the plate material 31 to cause friction. The joint is friction stir welded together with the plate material 31 by the heat and stirring action.
[0032]
At this time, the fitting gap is filled with the plate material 31 from the front surface side and the back surface side of the joint portion. Since the evaporation temperature of the adhesive is lower than the temperature due to the frictional heat applied by the bobbin tool 11, when the friction stir welding is performed, the adhesive is evaporated and the quality is not affected.
[0033]
According to the experiments by the inventors, as described above, G <C ≦ A and D ≦ B <2 × E + D, and the cross-sectional areas of the two plate members 31 are variously changed to friction stir. As a result of joining, it was found that if the cross-sectional area is set to be 1 to 3 times the total area of the fitting gap generated in the joined portion, the fitting gap can be filled and friction stir welding can be performed satisfactorily.
[0034]
It has been found that even when the total thickness of the plate material 31 is set to be not less than 1 and not more than 3 times the width of the fitting gap generated at the joint, the fitting gap can be filled and friction stir welding can be performed satisfactorily. In the friction stir welding, for example, the rotation speed of the bobbin tool 11 is 800 to 2000 rpm, and the feed rate (moving speed of the bobbin tool 11) is 100 to 1000 mm / min.
[0035]
In this way, after the face plate portions 21a and 22a are friction stir welded at the groove, they are reversed and similarly, the face plate portions 21b and 22b are friction stir welded, and the long die materials 21 and 22 are obtained by friction stir welding. Is a long friction stir welding material.
[0036]
In the above-described example, an adhesive is used for fixing the plate material 31. However, the plate material 31 may be temporarily fixed to the joint by spot welding.
[0037]
In the above-described example, the example in which the fitting groove 21d that is concave in the width direction and the fitting protrusion 22d that is convex in the width direction is used as the fitting structure, but the fitting structure shown in FIG. Good. That is, the fitting groove 41a that is concave in the thickness (height) direction is formed at one end of the face plate portion 21a, and the fitting protrusion 41b that is convex in the thickness direction is formed. Similarly, a convex protrusion 42a convex in the thickness direction is formed at one end of the face plate portion 22a, and a concave fitting groove 42b is formed in the thickness direction. Although not shown, similarly, the face plate portions 21b and 22b are also formed with fitting grooves that are concave in the thickness direction and fitting protrusions that are convex in the thickness direction. Then, as shown in FIG. 5, the fitting protrusions 42a are fitted into the fitting grooves 41a, and the fitting protrusions 41b are fitted into the fitting grooves 42b to combine the long mold materials 21 and 22 ( It may be made to match). Thereafter, as described above, the plate material 31 is fixed along the joint, and friction stir welding is performed.
[0038]
Further, the fitting structure shown in FIG. 6 may be used. That is, a notch is provided in the thickness direction from the back surface side at one end portion of the face plate portion 21a to form the locking projection 51, and a notch is formed in the thickness direction from one surface portion of the face plate portion 22a in the thickness direction. To form the locking piece 52. Although not shown in the drawings, the locking projections and the locking pieces are formed on the face plate portions 21b and 22b in the same manner. Then, as shown in FIG. 6, the locking projection 51 may be locked to the locking piece 52 and the long mold materials 21 and 22 may be combined (matched). Thereafter, as described above, the plate material 31 is fixed along the joint, and friction stir welding is performed.
[0039]
In the above example, the bobbin tool is used as a tool. However, when performing friction stir welding using a tool in which a probe is suspended from one shoulder portion, a plate material is similarly fixed to the joint portion. The frictional heat may be applied through the plate material. In other words, the bobbin tool cannot be used when there is a member (such as a rib member) that receives a pressing force from the shoulder portion at the joint portion, but in this case as well, the probe is suspended from one shoulder portion. What is necessary is just to make it apply a frictional heat via a board | plate material, fixing a board | plate material to a junction part using a tool.
[0040]
【The invention's effect】
As described above, according to the present invention, the diameter of the shoulder surface on the frictional force application surface side with the circular shoulder of the joint portion is a fitting structure in which the butt joint portion between the mold members is fitted in the width region direction or the height direction. The plate material of the following width range was fixed along the extending direction of the joint, and the frictional heat of the shoulder surface was applied to the joint through the plate, and the mold members were joined while plastically flowing the joint. Therefore, it is possible to easily set the thickness of the plate material according to the gap (gap) of the joint, and as a result, there is an effect that the gap can be sufficiently replenished in the joining process, and there is a joining defect. It does not occur.
[0041]
In addition, the present invention uses a bobbin tool having a pair of shoulder portions located on both sides of the joint portion with a probe interposed therebetween as a tool, and adds a plate material so that the distance between the pair of shoulder portions is greater than the thickness of the joint portion. Since the thickness is set to be smaller than the thickness, sufficient frictional heat can be applied from the shoulder portion to the joint portion via the plate material, and the friction stir welding can be performed satisfactorily.
[0042]
Furthermore, in the present invention, the plate material is made of the same material as the mold material or a material having a lower melting point, and the plate material is fixed by an adhesive whose evaporation temperature is lower than the temperature due to frictional heat or spot welding. The plate material will be friction stir welded together with the mold material, and if the plate material and the mold material are fixed with an adhesive, it can be fixed easily, and the evaporation temperature of the adhesive is higher than the temperature due to frictional heat. Therefore, the adhesive evaporates in the process of friction stir welding and does not affect the quality. And even if it fixes a board | plate material and a mold material by spot welding, there exists an effect that temporary fixation can be performed easily.
[0043]
Further, the present invention has an effect that the friction stir welding can be satisfactorily performed because the cross-sectional area of the plate material is set to 1 to 3 times the total area of the fitting gap generated in the joint. Furthermore, if the thickness of the plate material is 1 to 3 times the fitting gap generated at the joint, there is an effect that the friction stir welding can be performed satisfactorily.
[0044]
Furthermore, the present invention is that the width of the plate material is larger than the fitting portion width formed in the joint portion and is equal to or less than the shoulder diameter, so that the plate material does not protrude from the shoulder portion, and the friction stir welding can be performed satisfactorily. effective.
[0045]
Furthermore, since the present invention gradually reduces the thickness of the tool entry end of the plate material, there is an effect that a tool such as a bobbin tool can be easily inserted at the start point of the joint portion during friction stir welding.
[Brief description of the drawings]
FIG. 1 is a side view showing an example of a bobbin tool used in friction stir welding according to the present invention.
FIG. 2 is a perspective view showing a state in which a plate material is fixed to a butt joint portion between mold materials.
3 is a cross-sectional view showing a state in which friction stir welding is performed using the bobbin tool shown in FIG. 1. FIG.
FIG. 4 is a cross-sectional view showing an example of a state where friction stir welding is performed on butt joints between mold materials.
FIG. 5 is a cross-sectional view showing another example of a state in which a butt joint between mold materials is friction stir welded.
FIG. 6 is a cross-sectional view showing still another example of a state where friction stir welding is performed on butt joints between mold materials.
[Explanation of symbols]
11 Tool (bobbin tool)
12 Probes 13 and 14 Shoulder portions 21 and 22 Mold material (long mold material)
31 Plate material

Claims (4)

A circular shoulder that imparts frictional heat to the workpiece is rotated while imparting frictional heat to the front side or both sides of the butt joint between the mold members extending in the longitudinal direction, and the vicinity of the joint is plastically flowed. In the manufacturing method of forming a friction stir welding material by performing friction stir welding between workpieces,
The butt joint between the mold members is a fitting structure that is fitted in a width direction or a height direction, and a frictional force application surface side of the joint with the circular shoulder has a width region smaller than the diameter of the shoulder surface. The plate material is fixed along the extending direction of the joint portion, the tool entry end of the plate material is gradually thinned, and the frictional heat of the shoulder surface is applied to the joint portion via the plate material, A method for producing a friction stir welding material, characterized in that the mold materials are joined by plastic flow of a joint portion.   The tool is a bobbin tool having a pair of shoulder portions located on both front and back sides of the joint with the probe interposed therebetween, and the interval between the pair of shoulder portions is larger than the thickness of the joint and smaller than the thickness of the plate. The method for producing a friction stir welding material according to claim 1, wherein the friction stir welding material is set.   The plate material is the same material as the mold material or a material having a lower melting point, and is fixed to the joint by an adhesive having a lower evaporation temperature than the frictional heat or spot welding. The method for producing a friction stir welding material according to claim 1.   2. The method for manufacturing a friction stir welding material according to claim 1, wherein the width of the plate material is not less than a width of a fitting portion formed in the joint portion and not more than a shoulder diameter.

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